High 7.5Published Apr 7, 2026

CVE-2026-28389Possible NULL Dereference When Processing CMS KeyAgreeRecipientInfo

Updated under an hour ago (Oct 27, 2026, 7:10 AM ET)

Does this affect you?

It affects OpenSSL and 2 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for OpenSSL

Exploited in the last 30 days

Issue summary: During processing of a crafted CMS EnvelopedData message with KeyAgreeRecipientInfo a NULL pointer dereference can happen. Impact summary: Applications that process attacker-controlled CMS data may crash before authentication or cryptographic operations occur resulting in Denial of Service. When a CMS EnvelopedData message that uses KeyAgreeRecipientInfo is processed, the optional parameters field of KeyEncryptionAlgorithmIdentifier is examined without checking for its presence. This results in a NULL pointer dereference if the field is missing. Applications and services that call CMS_decrypt() on untrusted input (e.g., S/MIME processing or CMS-based protocols) are vulnerable. The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.

CVSS: 7.5 HIGH (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-476
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: openssl
NVD analysis: Modified
Record last updated: Oct 14, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

OpenSSL OpenSSL openssl:openssl (from the name)	from 3.6.0 before 3.6.2; from 3.5.0 before 3.5.6; from 3.4.0 before 3.4.5; from 3.3.0 before 3.3.7; from 3.0.0 before 3.0.20; from 1.1.1 before 1.1.1zg; from 1.0.2 before 1.0.2zp	CNA record
Siemens SIMATIC CN 4100 siemens:simatic_cn_4100 (from the name)	before V5.0	CISA ADP
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem siemens:simatic_s7_1500_tm_mfp_gnu_linux_subsystem (from the name)	all versions	CISA ADP
openssl openssl openssl:openssl	from 1.0.2 before 1.0.2zp; from 1.1.1 before 1.1.1zg; from 3.0.0 before 3.0.20; from 3.3.0 before 3.3.7; from 3.4.0 before 3.4.5; from 3.5.0 before 3.5.6; from 3.6.0 before 3.6.2	NVD

References

References

https://openssl-library.org/news/secadv/20260407.txt	vendor-advisory
https://github.com/openssl/openssl/commit/f80f83bc5fd036bc47d773e8b15a001e2b4ce686	patch
https://github.com/openssl/openssl/commit/16cea4188e0ea567deb4f93f85902247e67384f5	patch
https://github.com/openssl/openssl/commit/785cbf7ea3b5a6f5adf0c1ccb92b79d89c35c616	patch
https://github.com/openssl/openssl/commit/c6725634e089eb2b634b10ede33944be7248172a	patch
https://github.com/openssl/openssl/commit/7b5274e812400cacb6f3be4c2df5340923fa807f	patch
https://cert-portal.siemens.com/productcert/html/ssa-032379.html
https://cert-portal.siemens.com/productcert/html/ssa-265688.html

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.